left arrow stopped working today

[deloptes <deloptes@yahoo.com>]

Hello,
perhaps someone can give me a hint on an issues I'm having at the moment.
I've just came back from work and started my notebook at home and to my
surprise the left arrow key was not working on my usb keyboard. the right
is ok. On the notebook non of the keys was working. I logged out and in the
login screen everything was working. logged in again and it wasn't working
again.

so, 1st why does it stopped working how can I check. and second I've seen  
with xmodmap -pk

     97         0xff50 (Home)
     98         0xff52 (Up)
     99         0xff55 (Prior)
    100         0xff51 (Left)
    101
    102         0xff53 (Right)
    103         0xff57 (End)
    104         0xff54 (Down)
    105         0xff56 (Next)
    106         0xff63 (Insert)
    107         0xffff (Delete)

but http://www.comptechdoc.org/os/linux/howlinuxworks/linux_hlkeycodes.html 
suggests different keycodes for linux.

thanks in advance